The present invention relates to a probe card for establishing electrical contact with semiconductor wafers under test and, more particularly, to a modularized probe card with compressible electrical connection devices.
During a semiconductor fabrication process, semiconductor dices are formed on a wafer by photolithography, deposition, and etching. The wafer is a substrate formed of silicon or gallium arsenide. After the fabrication process and before it is singulated, the wafer will need to pass functional test to verify their electrical performance within design specification. Conventionally, a test head of a test apparatus for chip probing usually mounts a probe card with a plurality of probe needles or other contact members for contacting with electrodes, such as bond pads or bumps, of a wafer. The probe card provides electrical connections between the test apparatus and the wafer under test.
In U.S. Pat. No. 6,060,891 entitled xe2x80x9cPROBE CARD FOR SEMICONDUCTOR WAFER AND METHOD AND SYSTEM FOR TESTING WAFERSxe2x80x9d, a probe card with a silicon interconnect substrate is disclosed. Some contact elements shaping like bumps are formed on a bottom surface of the interconnect substrate. The interconnect substrate is electrically connected to a membrane, which is electrically connected to the interconnect substrate and a probe card fixture. A force-applying mechanism is installed above top surface of the interconnect substrate to press the interconnect substrate for establishing electrical communication between contact elements and electrodes on a wafer under test. Since the thermal expansion coefficient of the interconnect substrate and that of the wafer under test are the same, precise contact is provided and no skew will occur by temperature variation between the electrical contacts. Yet one disadvantage is that the membrane fixes and joints the interconnect substrate with probe card fixture and makes it impossible to disassemble the interconnect substrate. It will need to discard the probe card once damage or mistake occurs on the interconnect substrate, and this will make it impossible to effectively reduce the testing cost
A main purpose of the present invention is to supply a modularized probe card with compressible electrical connection device. It utilizes elastic contact members to elastically and electrically contact with a probe head and an interface board. The probe head is modularized installed in and electrically connected to the interface board. The modularization of probe head and interface board makes it possible to reduce cost in manufacturing probe cards.
The probe card in accordance with present invention comprises an interface board, a modularized probe head and at least a compressible electrical connection device. The interface board has a downset for installing the probe head. The compressible electrical connection device has an insulation layer with a plurality of circuits. Two ends of each circuit connect respectively to the first and the second contacting pads which combines with a plurality of elastic contact members. Each elastic contact member has a supporter, combining with a conductive layer, for electrically connecting the interface board with the probe head.